二重起動防止
// InitInstance の初めの方で
m_hAppMutex = ::CreateMutex(NULL, TRUE, _T("UNIQUE_PROGRAM_NAME"));
if (!m_hAppMutex)
return FALSE;
if (ERROR_ALREADY_EXISTS == ::GetLastError())
{
CString csWork;
csWork.LoadString(IDS_APPTITLE);
HWND hPrevWnd = ::FindWindow(NULL, (LPCTSTR)csWork);
if (hPrevWnd)
::SetForegroundWindow(hPrevWnd);
return FALSE;
}